Equation of line in the internal bisector of OA˙ and OB is (3+1)i^+(3+1)j^ ⇒ line will be y=x⇒x−y=0 D=a2+(1−a)2a−(1−a)=29 (2a−1)2=281(a2+(1−a)2)⇒2(4a2−4a+1)=81a2+81a2−162a−81⇒162a2−162a+81−8a2+8a−2=0⇒154a2−154a+79=0 Sum of values =−154(−154)=1